The present invention relates to stent deployment devices and methods for deploying stents. More particularly, the present invention concerns a stent deployment device and a method for deploying a stent within the alimentary tract using an endoscope.
Endoscopes are effective devices for diagnosing and treating patients with minimal intervention and discomfort and are often used to explore and perform biopsies in such areas as the alimentary tract. In general, an endoscope has a flexible elongated tubular body equipped with a miniature television camera or other viewing device, a light, and a working lumen or channel. The working channel is used to store and deploy a variety of surgical tools for different endoscopic operations.
A stent is a resilient device often used in anchoring vascular grafts and for supporting body openings during the grafting of vessels and tubes of the body during surgery. Also, stents are frequently used, without grafts, for supporting lumenal patency. More recently, artificial (woven or nonwoven polymeric) grafts are used in cardiac, vascular and nonvascular applications to provide extra support. Moreover, stents can be separated into self expanding and plastically deformed stents. A self expanding stent is deployed by its self expanding resilience. A plastically deformed stent is deployed by plastic deformation of the constituent material with a balloon or other such dilating instrument.
Endoscopes are effectively utilized to deploy stents within a body cavity in a minimally invasive manner. In a conventional method, a stent is compressed to fit into the working channel of the endoscope and is delivered to the body cavity to be treated. However, storing a stent within the working channel of an endoscope causes several problems. First, there is a limitation on the size of the stent that can be compressed to fit in the working channel. Because the working channel of the endoscope is often relatively small, a large stent may not fit within the working channel. Thus, this method is not suitable for deploying large stents.
Additionally, fitting a stent in the working channel often results in extreme deformation of the stent when it is deployed to the body cavity. Since stents are made of resilient material, compression within the working channel can cause the stent to become deformed and fail to return to its original shape if strained beyond a certain point. The more the stent gets strained, the more extreme the deformation is likely to be.
Consequently, there is a need for stent deployment systems and methods that provide a solution to aforementioned problems and permit deployment of stents, regardless of size, into body cavities.
In accordance with the present invention, as embodied and broadly described herein, the present invention utilizes an endoscope having a distal end and a working channel. A protective cap is mounted on the distal end of the endoscope. A flexible stent is circumferentially compressed over the perimeter of the protective cap. A sheath is releasably wrapped around the stent to hold it in its compressed configuration over the cap. One end of a flexible, elongated member, such as a wire or other flexible member, is attached to the sheath to permit removal from the cap and stent and deployment of the stent in substantially linear transverse alignment within a body cavity. The elongated member extends through the working channel of the endoscope and exits from the distal end thereof.
In accordance with another aspect of the present invention, the stent deployment device comprises one end of a flexible, elongated member attached to a release device for removing a sheath from a cap and deploying the stent in substantially linear transverse alignment within a body cavity.
In yet another aspect of the present invention, the stent deployment device comprises a protective cap adapted for mounting on the distal end of an endoscope with a sheath that is releasably wrapped around the stent to hold the stent in a compressed configuration over the cap. One end of a flexible, elongated member is attached to the sheath to permit its release and deployment in substantially linear transverse alignment within a body cavity by withdrawing the elongated member extending through the working channel of the endoscope, the elongated member exiting from the distal end of the endoscope.
In still another aspect of the present invention, one end of a flexible, elongated member extending through the working channel is attached to a release device for removing a sheath from a cap and deploying a stent in substantially linear transverse alignment within a body cavity by withdrawing the elongated member.
The present invention further comprises a method including the steps of mounting a protective cap on a distal end of an endoscope, compressing a stent circumferentially over the perimeter of the protective cap, releasably wrapping a sheath around the stent to hold the stent in a compressed configuration over the protective cap and withdrawing the flexible, elongated member engaged with the sheath through the endoscope to release the sheath from the protective cap, thereby causing the stent to deploy.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.